function [ s ] = struct_add( s1, s2 )

field_names = fieldnames(s1);
n_field_name = length(field_names);
for i_name = 1:n_field_name
    eval(['s.', field_names{i_name}, ' = s1.', field_names{i_name}, ...
        ' + s2.', field_names{i_name}, ';']);
end

end

